JFK was very sick: the Addison's disease
http://en.wikipedia.org/wiki/Addison's_disease
he took steroids, testosterone and alot cortisone against the disease
(the side effect gave him a "bull-like" libido )
also he suffers of heavy Back problems, JFK took a lot painkiller
http://www.doctorzebra.com/Prez/g35.htm
most of problems were treated by "Dr" Max Jacobson aka "Dr. Feelgood" or "Miracle Max"
he gave Kennedy injections with a miracle drugs (secret recipe: amphetamines and painkillers ! )
he take during Cuba Missile crisis :
steroids (give him a "steroid psychosis")
testosterone
alot cortisone
amphetamines and painkillers injections by Dr. Feelgood
phenobarbital ( to chill down)
lomotil (side effect can make you "mad as a hatter.")
paregoric (Contains opium.)
Tuinal
Seymour Hersh's "The Dark Side of Camelot" (1998)
presents a critical analysis of the Kennedy administration,
stating that Kennedy "was probably one of the unhealthiest men ever to sit in the Oval Office."
i think even had he survives Dallas in 1963
he had died during second term 1964-1968.